Beetlemania!

Blog Post by: Kim Palmer

August 26, 2010 - 10:01 AM

Some call these the Dog Days of summer. And I don't know about your garden, but mine is looking pretty mangy. The flowering plants are mostly spent, the tomatoes have gotten ugly and sprawly. But the biggest eyesore is the damage wrought by Japanese beetles.

These voracious invaders have been plaguing Minnesota gardeners with a vengeance for the last several growing seasons. They're handsome bugs, with metallic bronze bodies that shimmer in the sunlight. But they turn plants into lace doilies, chomping through the leaves until nothing remains but brown veins.

What makes them especially challenging for gardeners is that they feed on over 300 plants. In my garden, they appear to nibble here and there on a few species. But there's one plant that attracts them like a cheap, all-you-can-eat buffet: a contorted filbert tree.

I bought it a few years ago because I liked the look of its twisty branches, never dreaming I was adding the equivalent of insect catnip to my garden. The beetles -- and their telltale damage -- appeared almost immediately.

I generally avoid pesticides, so I tried picking them off by hand. But I didn't drop them into a bucket of soapy water, the extermination method recommended by many experts. I simply dropped them on the ground, which, of course, allowed them to fly right back on the plant.

If you want to deter Japanese beetles without killing them, University of Minnesota entomologist Jeff Hahn recommends a low-impact, botanical-based insecticide, such as Neem, which prevents them from feeding. (For more information about Japanese beetles, visit: www.extension.umn.edu/distribution/horticulture/dg7664.html)

Are Japanese beetles driving you buggy? What are they eating in your yard? And what do you about them?